New-Onset Myocarditis in an Immunocompetent Adult with Acute Metapneumovirus Infection.

Introduction. A number of viruses have been implicated in viral myocarditis; however, there has been no previous report of human metapneumovirus (hMPV) causing this condition. Discovered in 2001, hMPV is typically associated with upper respiratory illness, mainly affecting children. Case Presentation. We report the case of a 25-year-old man with acute systolic heart failure from viral myocarditis secondary to the hMPV. The patient was initially admitted to the general medical ward but developed increasing oxygen requirements resulting in transfer to the cardiac intensive care unit. Cardiac magnetic resonance imaging was used to help confirm the diagnosis. He was treated with intravenous diuretics, and afterload and preload agents, and he was subsequently discharged home after seven days of hospitalization. Discussion. hMPV is typically a respiratory pathogen; however, it was associated with in myocarditis in our patient. Due to the recent ability to detect this virus, we may see more cases of this, particularly during peak months of infection. Conclusion. This is the first case description of myocarditis associated with hMPV infection.